1. Field of the Invention
This invention concerns image-printing or imaging, i.e. printing letters, characters, figures (patterns) on a substrate. More specifically the invention concerns an improved process for image-printing and certain improved printing inks that contain particular fluorocarbon surfactants having the CF.sub.3 (cf.sub.2).sub.3 moiety.
2. Description of the Prior Art or
The art of printing has been defined as the act, art, or practice of impressing letters, characters, of figures (patterns) on a substrate, and can be termed more particularly as "imaging." Imaging demands a precision of transfer from printing plate to substrate not required when, say, a continuous coating is applied by printing or an application of coloring agent is made by brush or roller.
Printing inks are composed basically of two parts, a dye or pigment coloring agent which forms the record of print or other image pattern left on the substrate, and a vehicle which aids in transfer of the coloring agent. Printing inks are commonly divided into three main classes; typographic, planographic and intaglio, corresponding to the three major divisions of printing. Each of these three different classes of inks has properties different from the other two.
Recently, a process has been developed for coating the inactive side of pressure-sensitive adhesive tape with an ink containing a fluorocarbon surfactant. The tape can be converted to rolls, where the fluoro compound helps to keep the inactive side of the tape from sticking to the side bearing the adhesive. This adhesive tape-coating process is quite readily distinguished from the image-printing process of the instant invention. The ink employed in the tape-coating process is also clearly distinguishable from the inks of the instant invention which contain significantly different fluorocarbon surfactants therein.
The particular printing processes that are improved according to the teachings of this invention are as follows. The improved inks of this invention are those that are usually employed in such printing processes with the improvement being the incorporation therein of the particular fluorocarbon surfactants described with particularity hereafter.